Numerous substrates are known in the art for abating energy and sound produced by appliances and automobiles. Known substrates include non-woven textile fabrics, such as shoddy pads, and foamed polyurethane materials. See for example, U.S. Pat. Nos. 4,056,161; 4,966,799; 5,266,143; and 5,068,001. It is also known in the art to use flexible polyurethane foam as a sound absorbing material. See U.S. Pat. No. 6,337,356. However, it is not known in the art to prepare an energy absorbing flexible foam containing an organic isocyanate, a first polyol prepared with a double metal cyanide (“DMC”) catalyst and a second polyol prepared with a basic catalyst.
It is known in the art to use DMC catalysts to produce polyether, polyester and polyetherester polyols, which are useful in polyurethane coatings, elastomers, sealants, foams and adhesions. DMC catalysts are typically obtained by reacting an aqueous solution of a metal salt, such as zinc chloride, with an aqueous solution of a metal cyanide salt, such as potassium hexacyanocobaltate, in the presence of an organic complexing ligand. The preparation of typical DMC catalysts is described, for example in U. S. Pat. Nos. 3,427,256, 3,829,505 and 5,158,922. DMC-catalyzed polyols are typically produced in a batch or semi-batch process, a high molecular weight polyol starter and DMC catalyst are charged to a reactor all at once, heated and then reacted with a small amount of epoxide. After DMC catalyst activation, more epoxide is continuously added to the reactor to complete polymerization.
It is also known in the art to produce molded polyurethane foams having enhanced physical properties from isocyanate-terminated-prepolymers prepared from poly(oxy)alkylene polyether polyols having low unsaturations, as disclosed in U.S. Pat. No. 5,700,847. Similarly, it is known in the art to prepare polyurethane slab or molded foam by the reaction of an isocyanate and a DMC catalyzed polyol in the presence of a catalyst, a chain extender and a surfactant. See U.S. Pat. No. 6,008,263.
Similarly, it is known in the art to produce high resilience (HR) foam prepared by reacting an isocyanate with a poly(oxypropylene/oxyethylene) polyol component manufactured at least in part with a DMC catalyst. See U.S. Pat. No. 5,605,939. HR foams produced in accordance with U.S. Pat. No. 5,605,939 have resiliency values of greater than 50%.
However, there remains a need in the art to produce an energy absorbing flexible foam wherein a portion of the polyol prepared with a basic catalyst can be replaced with a more economical polyol produced with a DMC catalyst.